Impact of satellite passive microwave observations on the nowcasting of a Mediterranean flash-flood event

Mircea Grecu (University of Maryland, Baltimore County); E. N. Anagnostou, A. PapodopoulosIn this study, we investigate the impact of satellite passive microwave observations on the nowcasting of a flash-flood producing precipitation event that occurred on 17 October 2006 in Crete. While the impact of satellite passive microwave observations on precipitation nowcasting overland may not be significant in general, in a Mediterranean set-up, satellite passive microwave observations are expected to be highly beneficial. This is because, satellite passive microwave observations are sensitive to both precipitation intensity and moisture distribution over sea, facilitating thus a more direct quantification of precipitation processes.

The impact of SSM/I observations on the above mentioned event is investigated using an ensemble assimilation methodology. That is, an ensemble of parallel forecasts is generated using different initial conditions (i.e. analyses and forecasts from previous analyses), microphysical, and physical parameterizations. The relationships between radiances and model state variables are determined in the ensemble space and the state variables are updated based on SSM/I observations. Results confirm the positive impact of the SSM/I observations.